Turbo-coredrill



P 6, 1966 w, TIRASPOLSKY 3,270,824

TURBO-COREDRILL Filed July 9, 1963 4 Sheets-Sheet 1 Sept. 6, 1966 w. TIRASPOLSKY 3,270,824

TURBO-COREDRILL Filed July 9, 1963 4 Sheets-Sheet 2 Sept. 6, 1966 w. TIRASPOLSVKY TURBO-C OREDRI LL 4 Sheets-Sheet 5 Filed. July 9, 1963 Sept. 6, 1966 Filed July 9, 1963 W. TIRASPOLSKY TURBO-COREDRILL 4 Sheets-Sheet 4 IHHIIH IHIHIH IIIHIHI United States Patent 3,270,824 TURBO-CUREDRHLL Wladimir Tiraspolsky, Issy-les-Moulineaux, France, as-

signor to Turbodrill InternationalCorporation, Schaan,

Liechtenstein Filed July 9, 1963, Ser. No. 293,741 Claims priority, application France, July 20, 1962, 904,580, Patent No. 1,339,585 6 Claims. (Cl. 175-107) The present invention relates generally to turbo-coredrills as they are commonly used for extracting cores from the ground.

It is known to effect core drilling particularly in hard grounds by means of diamond core bits, and this technique is more and more frequently used. It is also known that the high rotational speeds of drilling turbines are particularly well adapted to the use of diamond core bits or the like because they contribute to increase the penetration rate and the footage drilled per tool.

Turbo-coredrills are also known wherein the shaft is hollow and contains the inner core tube. However such assemblies permit only to extract cores of limited length and a low percentage of recovery.

Attempts have also been made to put conventional coredrills under a drilling turbine. However when lengthening the non-guided portion of the turbine shaft, its critical speed is reduced, and when the coredrill rotates at a high speed in a tubeless well it undergoes an increased friction and wear. This method does not permit the tool to be given the high pressures which are often required by some drilling bits for their adequate irrigation. Nor does it permit some special methods to be used such as shot drilling.

An object of the invention is to remedy the aforesaid disadvantages and to provide an improved turbo-coredrill possessing both the advantages of conventional coredrills and those of a turbodrill.

One of the incompatibilities between both systems resides in the large difference between the volume of the circulating fluid demanded by a turbine and the smaller volume called for by a core bit. This also applies to the pressure which is small at the turbine outlet and has to be fairly high in order to irrigate adequately some types of core bits, particularly insert diamond core bits. A contradiction also prevails between the aim at reducing so far as possible the shaft diameter of a turbodrill so as to widen the annular space containing the driving elements of the turbine and the aim at increasing said shaft diameter in turbo-coredrills so as to enhance the core diameter by increasing the core of the shaft receiving the inner core tube.

Another object of the invention is to provide a turbocoredrill comprising a turbine having an extension in the direction of the tool, said extension terminating in a core bit and being directly driven by the turbine shaft having an axial channel through which an elongated supporting member extends, said member being axially retained with respect to the stationary body of the turbine above said shaft and supporting in turn at its lower end and underneath the turbine a core tube while the turbine body ex tends in the form of a tubular sleeve which surrounds the rotating core tube and serves as a guide therefor.

Throughout the specification, the expressions lower, upper, under, over, etc. should be construed as applied to a vertically positioned equipment, assuming the coring tool to be directed downwardly.

It is therefore possible to use in the turbine proper a shaft of conventional diameter and also to build up said turbine by means of elements of usual type, which represents an obvious advantage from the economical standpoint since the annular space occupied by the turbinedriving elements may have any desired size while the coredrill which is arranged under said turbine may have a maximum size useful internal diameter of with respect to the diameter of the well being drilled, the only size reduction being due to the provision of an outer guiding tube (sleeve) whose diameter may be larger than or equal to the one of the turbine.

The lower bearing which serves as a guide for the rotating barrel of the coredrill inside the sleeve may be when needed of the full flow type thereby permitting a free flow of the fluid that circulated through the turbine toward the annular space of the well above the core bit. Where it is useful to cause a portion and even almost the entirety of the fluid to flow through the core bit, the lower bearing is similar to the lower bearing of a normal turbine or is a labyrinth bearing or even a sealed bearing, the flow of fluid being deflected inwardly through suitable channels which introduce it at proper positions into the core bit.

The tubular body which connects the turbine shaft with the core bit and which is the equivalent of an outer core barrel is guided inside said sleeve, lengthwise, by bushes or bearings containing fluid passages and an annular space so sized as to permit flow of the power fluid coming from the turbine. This guiding action of the tubular body thus ensures its radial maintenance under the best conditions.

The core barrel is advantageously guided inside the tubular portion by one or several bushings or bearings.

Generally speaking and particularly for large lengths, the aforesaid sleeve and tube are preferably made up of several lengths screwed together, thus, permitting the use of a core-drill which may have any suitable length, also an alteration of the length, of the core drill following a round trip or the replacement of worn parts of said coredrill without necessity of disassembling the turbine.

Preferably the elongated supporting member is formed by a solid or hollow rod of relatively small diameter. Above the turbine shaft, said rod is secured to the stator part of the turbine, for example by means of a seat which may be provided with elements permitting the measuring of the azimuth, particularly for extracting oriented cores.

The space defined inside the turbine shaft by the supporting rod and the spaces delineated by the bearings and bushings which guide the core barrel are so calculated as to allow of a direct flow of part of the fluid reaching the turbine head to the core bit with an adequate flow rate and under a pressure equal to the pressure drop in the turbine. This flow rate may be adjusted, if desired, by means of a nozzle which may be fitted, for example, to the upper end of the shaft bore or near said end.

The core barrel may be provided at its lower end with a retaining device or core extractor of the spring or sleeve type. Moreover a core-weakening or breaking device may be provided adjacent the lower end of the core barrel so as to be operative in hard and compact rocks. Actually in some hard rocks such as basalts and porphyries the fractional stress of which may reach 3000 and even 3500 lbs/sq", the breaking resistance of the core may exceed the mechanical strength of the tube or rod. In order to avoid any breakage, the rod may be, according to a feature of the invention, elastically held on the turbine body by its upper end so as to be movable axially with respect to the aforesaid body and barrel together with the core-tube, where 'a high resistance is encountered, and the core barrel is provided at its lower end with such elements as may, incidental to said relative axial motion, engage the core so as to form into it a peripheral cut or groove which reduces its cross sectional area and ensures adequate weakening thereof.

Such elements may be arranged under the core extractor proper and may be constituted by reinforced parts (for example, by using diamonds) pivoted to the inner core tube and shifted inwardly owing to their cooperation with the core bit or a part axially rigid therewith as the aforesaid elastic members are distorted. In a suitable constructional form, said elements are carried by a sleeve or an equivalent member capable of rotating with respect to the core barrel itself, for example, owing to the provision of an antifriction thrust bearing.

According to common practice, the inner-core tube is provided at its upper end with a check valve governing the outflow of the fluid which may be in a state of overpressure inside said barrel.

The main fluid stream that has been operative in the turbine is directed toward the annular space defined between the barrel and the protecting sleeve of the coredrill. This fluid stream or a fraction of it may be led back to the core bit so as to partake of its irrigation for completing the one which is ensured by the fluid that flows through the axial bore of the shaft. This technical solution of the problem is advantageous when dealing with large diameter wells. A constriction may then be provided in the aforesaid ring space downstreams with respect to the irrigation channels. Alternatively this fluid stream may be partly or entirely drained away above the core bit while contributing to drag away the cuttings in the annular space of the well being drilled. According to another alternative method, at least a portion of said fluid may be drained away at the junction between the guiding sleeve and the turbine, particularly where the diameter of said sleeve is larger than that of the turbine and where the latter calls for high fluid volumes.

For limiting the axial autonomy between the inner core tube or its stem and the barrel connected to the rotor part of the turbine which normally prevails within the limits of the axial clearance provided by the thrust bearings of this turbine, said barrel may have a downwardly directed seat against which an equivalent seat provided adjacent the top of the inner core tube may come into contact, interposed elements providing an antifriction thrust bearing. Such an arrangement naturally permits a relative displacement in the reverse direction between the stem and the core barrel which starts formation of a groove or cut in the core for weakening the same.

Where it is desired to be able to rotate the drill-stem while coring formation the core barrel may he, obviously, rotatively suspended in known fashion either over or under the turbine.

A further object of the invention is to provide a novel turbo-coredrill permitting the use of all types of core drilling tools, owing to easy adaptation to their specific operative parameters whereby modification of the number of stages and type of turbine blades and eventual addition thereto of an axial thrust compensator permits the most favorable assembly of working parameters such as: rotational speed, torque, weight, power, to be obtained.

Yet a further object of the invention is to provide a novel turbo-coredrill as aforesaid including a dual irrigation circuit permitting the volume as well as the pressure of the circulating fluid to be adjusted, whereby high circulation rate core bits (of the blade or roller type, etc.) or core bits comprising inset stones may be selec tively employed, the latter calling for a high pressure drop for being irrigated. Such a dual circuit also permits the use of shot drilling core bits which are known to be particularly economical in highly abrasive rocks but call for low irrigation volumes. In such a case, a single screening device may be then provided for permitting the tool to be continuously fed by drilling pellets through the hollow shaft of the turbine.

Obviously the improved turbo-coredrill may be equipped with such ancillary devices as may be necessary in several particular cases such as orientation markers, safety plugs for running in or the like.

Such a core drill can obviously be also used with any other type of rotating subsurface motor, driven by electric current, air under pressure or any other means.

With these and such other objects in view as will inci- FIG. 2 is a vertical sectional view drawn to a larger scale of the upper portion of the turbine corresponding to the part designated by II in FIG. 1.

FIG. 3 is a vertical sectional view of the lower portion of the turbine and the upper portion of the coredrill designated by III in FIG. 1.

FIG. 4 is a vertical sectional view drawn to a larger scale of the lower portion of the coredrill and tool designated by IV in FIG .1.

FIG. 5 is a sectional view showing the method of weakening the core in view of its extraction from a hard ground.

FIG. 6 is a fragmentary vertical section view of a constructional modification.

In the showing of FIG. 1, 1 designates generally the turbine, 2 designates the coredrill, and 3 designates the tool.

In FIG. 2, 4 is the upper end of the turbine body which contains over the set of stator blades 5 and the set of rotor blades 6 an upper bearing 7. The stator blade stack is held in position by a joint 8 which receives in its inner space the stator stack locking nut 9. The joint 8 is surmounted by another joint 10 which extends in the form of an upper joint 11 that connects the entire turbo-coredrill to the drill-stem. A seat 12 having fluid channels 13, and the purpose of which will be described hereafter, is held between the joints 10 and 11.

At 14 is shown the turbine shaft which has an axial bore 15. Above the stack of rotor blades the shaft 14 carries the sleeve 16 of the upper bearing. The stack of rotors is held in position by a nut 17 and a lock nut 18 which are fitted upon the threaded end of said shaft 14, said portion also receiving a cap 19 having a female thread for receiving a nozzle 20 with a male thread.

Through the central bore 15 of the turbine shaft 14.

extends a rod 21 which holds the inner core tube as described hereafter. The rod 21 has a non-circular portion, for example, a square portion 22 engaged into a corresponding bore 23 in the seat 12. This holds the rod 21 against rotation. The rod 21 is abutted upwardly against a shoulder 24 on the seat 12 and is held in that abutted position by means of a nut 25 and a cap-shaped locking nut 26. The nut 25 rests by means of an antifriction washer 27 (made for example of bronze) against a stack of elastic elements 28 such as Belleville ringshaped springs held in a sleeve 29 screwed upon the seat 12 and abutted against said seat. The rod 21 is provided adjacent its upper end with a square portion which permits it to be held stationary by means of a span ner while the nut 25 is being screwed.

In its portion where it penetrates into the turbine shaft 14, the rod 21 is sheathed by a tube 31 screwed into the seat 12. This tube defines with the-nozzle 20 an annular passage 32 for the penetration of the fluid which circulates inside the shaft 14 with a satisfactory rate of flow for irrigating the coring bit.

The seat 12 may be fixed in non-rotatable fashion, for example, by means of keys or pegs, in the joint 10, and may comprise an angular position index permitting the upper part of the rod to be properly orientated by reference to said index.

In the showing of FIG. 3 is illustrated as hereinbefore the connection between the turbine and the coredrill. At 34 is shown diagrammatically the lower thrust hearing of the turbine, and at 35 its lower radial bearing. The stack of stator elements is held at its lower end by a shoulder sleeve 36 connected to the upper joint. 3 Qf the coredrill sleeve. The coredrill is made up of a series of connecting subs such as the one designated by 38 which carries rubber pads or shoes 39 behaving as bearings and tubes 40 so as to constitute a continuous cylinder having a constant outer diameter. It will be noticed that the threads on the coredrill sleeve advantageously have a leftward pitch for staving off any risk of unscrewing responsive to friction.

The turbine shaft 14 is provided at its lower end with a shoulder sub 41 forming a lower abutment for the stack of rotor elements and connected to the head 42 of the coredrill.

The outer barrel of the coredrill which is connected to its head 42 is made up of a series of sleeves 43 arranged opposite the bearing shoes 39 and provided for example with an antiabrasive coating (for example, a chromium coating) which guides said tube, also with sleeves 44 carrying rubber pads or shoes 45 for guiding the inner core barrel, and also with tubes 46 which form the major portion of the outer tube of the coredrill.

' At the upper end of the coredrill the rod 21 has a base 47 screwed into a head 48 having an inner thread which receives a wear-taking sleeve 49 arranged opposite the shoes 45 and extended in the form of an inner core tube 50. The entire core tube is made up lengthwise of a series of tubular elements 49 and 50.

In the constructional form shown, the head 48 has an inner recess 51 which receives a ball valve 52 urged by a spring 53 against a seat 54 screwed into the adjacent wall of the recess 51. Channels 55 provide a communication between the recess 51 and the annular space defined between the head 48 and the outer tube of the coredrill. A constriction behaving as a venturi and generating a local depression is provided in front of the outlets of the channels 55.

In the showing of FIG. 4 is represented the lower portion of the improved coredrill. The skirt constituted by the tubes 40 carries at its lower end a sleeve 38 associated with the shoes 39 and a joint 57 which, in the present instance, has axial Windows 58. The outer tube 46 of the coredrill is provided at its lower end with a joint 43 guided by the bearing 39 and having screwed thereon another joint 59 which receives the core bit 60. The joint 59 has grooves for receiving guiding pads or shoes 61.

The inner core tube 50 has a lower joint 62 which is described hereafter and which receives in turn another joint 63 serving as a guide and arranged in front of the shoes 61.

In the constructional form shown, flutes 64 are provided on the joint 59. These flutes are adapted to cooperate with keys inserted through the windows 58 and held by a collar whereby the sleeve 59 may be prevented from rotating by means of a wrench when the core bit 60 is locked or unlocked.

The joint 62 is provided internally with retaining slips 65 of known type adapted to hold the core by means of dogs 66 and slidably received in a conical seat 67.

The inner core barrel terminates in a sleeve 68 suspended by means of a shoulder 69 to a cap 70 screwed into the joint 63. A roller bearing 71 is provided for permitting the shaft to impart rotation to the sleeve 68.

At its lower end the sleeve 68 is provided with hardfaced elements 72 hinged thereto by axes 73 and inwardly displaceable responsive to a relative axial motion between the drilling bit 60 and the inner core tube owing to a squeezing action on the elastic elements 28 by which the rod 21 is suspended. Upon the occurrence of such a relative axial motion, a shoulder 74 having a suitable outline of the drilling bit cooperates with the elements 72 so as to pivot them inwardly (as shown by FIG. 5) so as to cause them to engage the core and to form in it a peripheral weakening score or cut. This may be useful in very hard grounds for permitting the extraction of the core. Obviously the assemblies and the parts of the outer tube of the coredrill are so sized as to possess a higher mechanical strength than the force necessary for breaking the hardest core into which such a weakening score or cut has been made.

A locking is provided between the sleeve 68 and the joint 59 so as to permit said sleeve to start rotating when it comes into contact with the core bit for inwardly deflecting the hard faced elements 72.

The operation of the aforesaid assembly takes place as follows: The incoming circulating fluids which arrives through the annular space 76 partly flows through the blades of the turbine and then through the annular space 77 defined between the coredrill skirt and its outer barrel before escaping through the windows 58 and the channels 58'. Another fraction of this fluid flows through the annular nozzle 32 and the central bore 15 in the turbine shaft 14 and then through the annular space 78 defined between the inner tube and the outer barrel of the coredrill until it reaches the drilling bit. This represents the most simple possible irrigation scheme.

When the turbine whose motor is formed by the sets of blades 5 and 6 rotates, the shaft 14 is driven as well as the outer barrel 46 of the coredrill, whereby the rotation is transmitted to the core bit 60. The inner core tube 50 of the coredrill is held non rotating by the rod 21 whose non-circular portion 22 is angularly blocked in the part 23 of the seat 12.

With the drilling progress, the core moves up in the inner tube 50 whereby the fluid trapped in said tube may then escape through the valve 52-54 and the channels 55.

When the core has reached adequate length, the assembly is lifted and the core is held down by the wedges 65. If thecore does not break, the relative axial motion which then takes place between the inner and outer tubes of the coredrill inwardly shifts the elements 74 as in the previous occurrence, whereupon these elements are revolved by the core bit to cut a weakening groove into the core.

In the constructional form shown by FIG. 6, the head 48' of the coredrill tube has an upwardly directed hearing seat 81 fitted with an antifriction lining. The joint 42 has another seat 81 provided with a bearing element 82 which can rest upon the shoulder to preclude a relative motion of the rod 21 upwardly.

Minor constructional details may be varied without departing from the scope of the appended claims.

What is claimed is:

1. A turbo-coredrill including a turbine comprising a casing body, a set of stator blades fixed inside said casing body, a hollow shaft journalled in said body, and a set of rotor blades carried by said hollow shaft and cooperating with said stator blade set, a supporting rod axially extending through said hollow shaft and axially movable therein, means for selectively securing said rod to said turbine body preventing relative rotation thereto, said means being provided above said stator and rotor blades, said securing means including a seat fixed relative to said body having a noncircular bore, a corresponding noncircular rod portion defined on said rod selectively receivable within said bore, a large diameter guiding skirt forming a downward extension of the turbine body, a tubular member forming a downward extension of the turbine shaft, a core bit fixed to said tubular member, a core barrel suspended from said supporting rod, and guiding bearings interposed between said tubular member and said skirt and also interposed between said tubular member and the core tube.

2. A turbo-coredrill including a turbine comprising a body, a set of stator blades secured inside said body, a hollow shaft journalled in said body, and a set of rotor blades carried by said hollow shaft and cooperating with said stator blades, a supporting rod axially engaged through said hollow shaft, means for mounting said rod upon said body, elastic elements interposed between said rod and said mounting means to permit an axial motion of said rod with respect to the turbine body, said mounting means being arranged over said stator and rotor blades, a large diameter guiding skirt forming a downward extension of the turbine body, a tubular member forming a downward extension of the turbine hollow shaft, a core bit fixed to said tubular member, a core tube suspended from said supporting rod, and guiding bearings interposed said tubular member and said skirt and also interposed between said tubular member and said core barrel.

3. A turbo-coredrill according to claim 2, wherein an axial thrust bearing is interposed between said tubular member and the core barrel for limiting the axial motion of said barrel.

4. In a turbo-coredrill as in claim 2 wherein an annular axial extending fluid flow path is defined in said body intermediate said skirt and said tubular element having an outlet disposed adjacent said core bit, said guiding bearings interposed between said tubular member and said skirt lying within said flow path and permitting fluid flow therethrough whereby fluid within said fiow path lubricates said bearings and said core bit.

5. A turbo-coredrill including a turbine compising a casing body, a set of stator blades fixed inside said casing body, a hollow shaft journalled in said body, and a set of rotor blades carried by said hollow shaft and cooperating with the stator blades, a supporting rod axially engaged through said hollow shaft, means for mounting said supporting rod upon said body, elastic elements interposed between said supporting rod and said mounting means to permit an axial motion of said rod with respect to the turbine casing body and to said hollow shaft, a'large diameter guiding skirt forming a downward extension of the turbine casing body, a tubular member forming a downward extension of the hollow turbine shaft, a core bit rigid with said tubular member, a core tube suspended from said supporting rod, coreretaining means provided inside the core barrel, corebreaking means arranged at the lower end of said core barrel, and guiding bearings interposed between said tubular member and said skirt and between said tubular member and said core tube.

6. A turbo-coredrill according to claim 5 in which the core-breaking means comprise a shoe rotatably carried by the lower end of the core barrel, hard-faced elements hinged to said shoe, and a shaped element provided on said core bit for inwardly deflecting said hinged elements responsive to an axial relative motion between the supporting rod for the core barrel and the hollow shaft which carries the core bit supporting tubular portion so as to cause said hinged elements to engage the core received in the core barrel for breaking the same.

References Cited by the Examiner UNITED STATES PATENTS 2,626,780 1/1953 Ortloff 175-407 2,910,273 10/1959 Bon 175-107 V FOREIGN PATENTS 1,195,283 11/1959 France.

CHARLES E. OCONNELL, Primary Examiner.

J. A. LEPPINK, Assistant Examiner. 

1. A TURBO-COREDRILL INCLUDING A TURBINE COMPRISING A CASING BODY, A SET OF STATOR BLADES FIXED INSIDE SAID CASING BODY, A HOLLOW SHAFT JOURNALLED IN SAID BODY, AND A SET OF ROTOR BLADS CARRIED BY SAID HOLLOW SHAFT AND COOPERATING WITH SAID STATOR BLADE SET, A SUPPORTING ROD AXIALLY EXTENDING THROUGH SAID HOLLOW SHAFT AND AXIALLY MOVABLE THEREIN, MEANS FOR SELECTIVELY SECURING SAID ROD TO SAID TURBINE BODY PREVENTING RELATIVE ROTATION THERETO SAID MEANS BEING PROVIDED ABOVE SAID STATOR AND ROTOR BLADES, SAID SECURING MEANS INCLUDING A SEAT FIXED RELATIVE TO SAID BODY HAVING A NONCIRCULAR BORE, A CORRESPONDING NONCIRCULAR ROD PORTION DEFINED ON SIAD ROD SELECTIVELY RECEIVABLE WITHIN SAID BORE, A LARGE DIAMETER GUIDING SKIRT FORMING A DOWNWARD EXTENSION OF THE TURBINE BODY, A TUBULAR MEMBER FORMING A DOWNWARD EXTENSION OF THE TURBINE SHAFT, A CORE BIT FIXED TO SAID TUBULAR MEMBER, 